Room Acoustics, (sound treatment)

Hi there. I am looking for a way to make the room I record in, as sound proofed, "treated" as possible, for as cheap as possible.

I live in a really quiet area (it's basically silent during the day) and the room I will be recording in is a utility room in my garden, about 1 metre from the house. There is double glazing glass on the room's windows/door and the windows to the house. Preferably I would like not to be heard from the house.. (This will not need much work because it's quite hard to hear at the moment, but i would like it to be possible not to be heard at all)

My second concern is to not be heard by neighbours. I've heard hanging carpet or duvets on the walls is good?

When heavy bass is being generated, everybody is going to hear it. Only, Rubber/spring isolated rooms constructed within rooms can provide that kind of isolation from disturbing others and others disturbing you. Hanging carpeting on the walls will only work if you like carpet on your walls. It's good when you don't like to hear high frequencies at all. You need mass for bass control and/or religious affiliation. I am not an acoustical architect I'm a practical hack. If you like brain death loudness levels, go to a rock 'n roll concert. Money will get you anything you want. How much you got?

So there might be a possible solution in utilizing electronic noise canceling control. You know, like all of those new noise canceling headphones. Instead, you set up a PA system outside of your abode. Any sound that you are making inside your studio, should have microphones on. Those microphones will feed your console which will feed the PA system. Now to control the noise, you will need to feed the PA system a feed from your console that is phase inverted to the acoustic noise emanating from your laboratory. When the polarity inverted electronically amplified external PA system combined with the escaping acoustic noise pollution, they will cancel a great deal of the offending acoustic energy and voilà. Controlling noise by adding anti-noise. Of course if you are dealing with matter, it could cause the destruction of our known universe.